Dataset Information

Molecular characterization of a genomic region associated with virulence in Dichelobacter nodosus.

ABSTRACT: The major pathogen implicated in footrot, a highly contagious disease of sheep, is the strict anaerobe Dichelobacter nodosus (formerly Bacteroides nodosus). Sequence analysis of a 2,262-bp segment of the D. nodosus genome which is more prevalent in virulent isolates than in other isolates showed the presence of four open reading frames which appeared to have consensus transcriptional and translational start signals. These virulence-associated genes have been designated vapABCD. Two of the three copies of the vap region in the genome of the reference strain D. nodosus A198 were shown to carry all of the vap genes, whereas one copy contained only the vapD gene. The VapD protein was gel purified, shown to contain the predicted amino-terminal sequence, and used to raise rabbit antibodies. Western blots (immunoblots) showed that all of the D. nodosus strains tested that contained the vap region produced the VapD protein. The VapD protein had significant amino acid sequence identity with open reading frame 5 from the cryptic plasmid of Neisseria gonorrhoeae, and the vapBC operon had sequence similarity with the trbH region of the Escherichia coli F plasmid. It is proposed that these gene regions evolved from the integration of a conjugative plasmid from another bacterial species into the D. nodosus chromosome.

SUBMITTER: Katz ME

PROVIDER: S-EPMC258206 | biostudies-other | 1992 Nov

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Molecular characterization of a genomic region associated with virulence in Dichelobacter nodosus.

Katz M E ME Strugnell R A RA Rood J I JI

Infection and immunity 19921101 11

The major pathogen implicated in footrot, a highly contagious disease of sheep, is the strict anaerobe Dichelobacter nodosus (formerly Bacteroides nodosus). Sequence analysis of a 2,262-bp segment of the D. nodosus genome which is more prevalent in virulent isolates than in other isolates showed the presence of four open reading frames which appeared to have consensus transcriptional and translational start signals. These virulence-associated genes have been designated vapABCD. Two of the three ...[more]

PMID: 1398971

Similar Datasets

Project description:UNLABELLED:Footrot is a contagious, debilitating disease of sheep, causing major economic losses in most sheep-producing countries. The causative agent is the Gram-negative anaerobe Dichelobacter nodosus. Depending on the virulence of the infective bacterial strain, clinical signs vary from a mild interdigital dermatitis (benign footrot) to severe underrunning of the horn of the hoof (virulent footrot). The aim of this study was to investigate the genetic relationship between D. nodosus strains of different phenotypic virulences and between isolates from different geographic regions. Genome sequencing was performed on 103 D. nodosus isolates from eight different countries. Comparison of these genome sequences revealed that they were highly conserved, with >95% sequence identity. However, single nucleotide polymorphism analysis of the 31,627 nucleotides that were found to differ in one or more of the 103 sequenced isolates divided them into two distinct clades. Remarkably, this division correlated with known virulent and benign phenotypes, as well as with the single amino acid difference between the AprV2 and AprB2 proteases, which are produced by virulent and benign strains, respectively. This division was irrespective of the geographic origin of the isolates. However, within one of these clades, isolates from different geographic regions generally belonged to separate clusters. In summary, we have shown that D. nodosus has a bimodal population structure that is globally conserved and provide evidence that virulent and benign isolates represent two distinct forms of D. nodosus strains. These data have the potential to improve the diagnosis and targeted control of this economically significant disease. IMPORTANCE:The Gram-negative anaerobic bacterium Dichelobacter nodosus is the causative agent of ovine footrot, a disease of major importance to the worldwide sheep industry. The known D. nodosus virulence factors are its type IV fimbriae and extracellular serine proteases. D. nodosus strains are designated virulent or benign based on the type of disease caused under optimal climatic conditions. These isolates have similar fimbriae but distinct extracellular proteases. To determine the relationship between virulent and benign isolates and the relationship of isolates from different geographical regions, a genomic study that involved the sequencing and subsequent analysis of 103 D. nodosus isolates was undertaken. The results showed that D. nodosus isolates are highly conserved at the genomic level but that they can be divided into two distinct clades that correlate with their disease phenotypes and with a single amino acid substitution in one of the extracellular proteases.

Dataset Information

Molecular characterization of a genomic region associated with virulence in Dichelobacter nodosus.

Publications

Molecular characterization of a genomic region associated with virulence in Dichelobacter nodosus.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets